The present invention relates to a vehicle seat comprising a seat part, a backrest, a height adjustable headrest which is displaceably guided by at least one guide rod in associated guide receivers in the backrest, and an active head support system through which the headrest is brought into a predetermined protection position in the event of an accident, with the guide receivers in each case being formed by a sleeve element which is inserted into a recess in the backrest,
Seats for means of transport, in particular, are increasingly being fitted with an active head support system, by means of which the headrest is brought into a position displaced forwardly and upwardly in the event of a rear end impact, at which position the headrest is as close as possible to the head of a person sitting in the seat and thus offers enhanced protection. A known system of this kind comprises rods accommodated in the backrest of the seat which move the headrest into the predetermined position via the guide receivers for the headreset rods. Guide elements are accommodated in the backrest so that the headrest executes this desired movement when the system is triggered.
It is the object of the invention to simplify a seat of the kind first mentioned with respect to its construction and so to lower the manufacturing costs.
This object is satisfied by the sleeve element being made with a guiding function for the movement of the headrest when the active head support system is triggered, in addition to the guiding function for the traveling in and out of the headrest.
There is no need for separate guide elements thanks to the additional design of the sleeve element with a guiding function for the movement of the headrest when the active head support system is triggered. The sleeve element advantageously has a dual function. The costs of manufacture and storage are thereby advantageously reduced.
In accordance with one embodiment of the invention, the sleeve element has a sleeve section to guide a headrest rod and a guide section, arranged in particular on the outside of the sleeve section to guide the sleeve in a guide which is provided in the backrest and whose shape determines the movement of the sleeve when the active head protection system acts on the headrest during an accident. The headrest movement is advantageously simultaneously predetermined by the sleeve movement predetermined in this way in the event of the active head protection system being triggered so that the headrest safely reaches the desired protection position.
The shape of the guide and of the guide section preferably ends with a vertical section at the upper end. In this way, the headrest is prevented from being manually displaced in the direction of the protection position. Such an unwanted displacement can, for example, take place by pressing onto the headrest from behind in a horizontal direction. The force exerted is directed perpendicularly to the guide shape due to the upper vertical section and so has no effect.
The guide section can, for example, be made in the form of two blocks spaced from one another and arranged like wings on the guide sleeve and the guide in the backrest can be made as a rail comprising the guide section of the sleeve element. A stable and secure guiding can be ensured in this way.
In accordance with a further embodiment of the invention, the sleeve element is additionally provided with latch means by which the headrest position set by the active head protection system can be blocked against being reset. This blocking of the headrest position ensures that the headrest can exercise its protective function ideally in the set protection position even in the event of a multiple impact. The arrangement of the latch means required for this on the guide sleeve has, in turn, the advantage that separate latch means are not required. The guide sleeve is thereby given a further function which again has a favorable effect on the costs of manufacture and storage.
The latch means are preferably made releasable to free the head rest position. The headrest can be moved back into its starting position in this way after the end of the danger situation.
In accordance with a special embodiment of the invention, the releasable latch means are formed as a tongue arranged in particular between the two blocks and having outwardly directed latch projections. A compact design results in this way with a simultaneously good engagement possibility of the latch means.
It is also preferred to have the guide section and/or the latch means formed on the sleeve element. This also has advantages in the manufacture and assembly of the seat as the total number of parts is reduced.
In accordance with another embodiment of the invention, the sleeve element is formed to support a Bowden cable which can, for example, serve the electrical traveling in and out of the headrests or the actuation of a release device for a manual headrest with an automatic retraction when the backrest is folded forward. In this way, a separate component is again saved and thus the total number of parts reduced. The sleeve element is given a multi-function in this way by means of which the costs of manufacture and assembly can be cut further.
In accordance with a further embodiment of the invention, the sleeve element has means whereby the triggering of the active head protection system can be signaled. For example, the sleeve section visible after triggering can have a signal color or an indicator can be released. The sleeve element is given a further function in this way so that a further separate component can be saved.
In accordance with a further embodiment of the invention, means are provided on the sleeve element whereby, to prevent the risk of injury, a triggering of the active head protection system is prevented when the headrest has been removed. For example, a locking lever can be arranged on the sleeve which is moved from a release position into a position blocking the movement of the sleeve element out of the receiver in the backrest when the headrest rod is removed. The sleeve element is given yet another function in this way and replaces yet another separate component.